UPDATED: PC makers may not get the final version of Windows Vista until mid-November,
putting at risk Microsoft's goal of a November launch, according to a
report.

The bug, discovered as testers inspected the Vista RC2 for final shakedown,
could result in Windows XP-based systems freezing when they attempt to
upgrade to Vista.

Microsoft, which earlier said it would send PC
manufacturers the release to manufacturing (RTM) version of its
next-generation operating system this month, may have to wait until Nov. 8
to squash the fatal flaw.

"We are on track for Windows Vista business availability in November and
general availability in January 2007," said a Microsoft spokesperson,
responding to the Taiwan-based dispatch from DigiTimes.

However, the
software giant refused to publicly confirm a date for Windows Vista RTM.

Despite any last-minute delay, Vista could be ready for business users in
November. The software maker could release Vista Nov. 28 or Nov. 30 and
still meet their self-imposed November deadline, analyst Joe Wilcox of
JupiterKagan told internetnews.com.

However, the January general
launch of its operating system could face more difficulties, he said.

PC makers need two months to get Vista ready to ship, he said. If Microsoft
is to have any luck, it'll need to have Vista ready well before the
Consumer Electronics Show, set for Jan. 8-11, according to the analyst.

Earlier this week, Microsoft announced a holiday coupon
program designed to forestall concerns from PC makers worried computer sales
might fall due to Vista being unavailable until January.

On Tuesday,
Microsoft said consumers and small businesses that purchase a PC preloaded
with Windows XP or Office 2003 between Oct. 26, 2006, and March 15, 2007, would
be eligible for its Express Upgrade program.

The program provides a 50
percent discount for buyers upgrading from Windows Home Edition to either
Vista Home Basic or Vista Home Premium.

For businesses that purchase their computers through participating OEMs, the
coupon program lets them upgrade to Office 2007 when it is released next
year.

Along with responding to concerns of PC makers, Microsoft also this month cleared
a major hurdle that possibly threatened to hold Vista hostage.

The company
said it was confident it had answered the questions of European and Korean
regulators, which might have delayed Vista's launch. Following constructive
dialogue with the regulators, Microsoft announced it would make some changes
to its new operating system.

The response followed concerns from a range of
vendors that felt inclusion of a variety of security, Internet and document
features could provide an unfair advantage for the software company.